1. Field of the Invention
The present invention relates to a receiving apparatus for receiving radio signal including image information which a movable transmitting unit transmits through a plurality of receiving antennas.
2. Description of the Related Art
In recent years, in the field of the endoscope, a swallow-type capsule endoscope has appeared. This capsule endoscope is provided with image pickup function and radio communication function. The capsule endoscope has a function of being moved following the peristaltic motion inside of the body cavity, for example, the inside of the organs such as the stomach, small intestine after it is swallowed through the mouth of a patient for observation (examination) until it is naturally excreted from the body so as to take the images sequentially.
Image information taken by the capsule endoscope inside of the body while it is moved inside of the body cavity is transmitted to outside in succession by radio signals and stored in a memory provided in a receiving apparatus outside. By carrying the receiving apparatus equipped with the receiving function and memory function, the patient can move freely after he or she swallows the capsule endoscope until the capsule type is excreted. After that, a medical doctor or nurse can display images of the organ based on the image data stored in the memory on a display device for diagnosis.
Generally in the receiving apparatus, a plurality of receiving antennas for receiving a radio signal transmitted from the capsule endoscope are disposed dispersedly outside of the body and a single receiving antenna having fewer reception errors in the radio signal is selected so as to receive the radio signal. In the meantime, a receiving apparatus which detects the position of a capsule endoscope inside the body which transmits out the image signal according to the strength of signal received by each receiving antenna by switching receiving of the plurality of receiving antennas disposed outside of the body has been disclosed (see Japanese Patent Application Laid-Open No. 2003-19111).